The role of palladium catalyst and base in stereoselective transformations of (E)-2-chlorovinylsulfides

Stereoselective transformations of 2-chlorovinylsulfides in the presence of soluble (t-BuOK) or insoluble (solid KOH or Cs2CO3/18-crown-6) base and palladium catalyst (dppb)Pd(OAc)2 have been studied. Depending on the substrate or catalytic system, the reaction leads to the formation of (E)-1,2-bis[aryl(or arylmethyl)thio]ethenes and/or (E)-1,4-bis[aryl(or arylmethyl)thio]-1-buten-3-ynes in yields of up to 93%.